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May 21, 1963
0.0. GRUENZ, JR
3,090,942
NUMBER COMPARISON AND DISPLAY CIRCUITS
Filed Dec. 18, 1958
7'EPP/N G
DEV/CE
NUMBER
SOURCE
ED
NUMBER
SOURCE
INVENTOR
O. 0. GRUENZ,JR.
BY @{W
ATTORNEY
ilnited grates Fatent
1
fire
3,888,942
Fatented May 21, 1963
2
NUMBER CQMPARESGN AND DESPLAY CH'KCUITS
Otto 0. Gruenz, In, Livingston, NJL, assignor to Bell
that therein shown is a block representation of a reference
number source 1, a similar representation of a compared
number source 2, a representation of a sequential stepping
device 3, and a matrix comprising a plurality of vertical
Telephone Laboratories, Incorporated, New York,
columns A, B . . . N each having ten basic comparison
3,090,942
N.Y., a corporation of New York
Filed Dec. 18, 1958, Ser. No. 781,387
13 Claims. (Cl. 349-1462)
circuits similar to those shown in detail within the A0
dashed rectangle 4.
The A column relates to the ?rst (or A) digit in any
number which is to be compared in the circuits, the B
This invention relates to comparison devices. Although
to the next digit, the C column to the third digit
the principles underlying the invention may ?nd applica 10 column
. . . and the N column to the nth digit. The numbers
tion in a variety of embodiments, the particular embodi
0-9 relate to the value of the digit and as will be ob
ment herein selected for an illustrative description com
served from the ?gure, the embodiment herein described
prises circuits which are effective to compare each digit
contemplates the use of information expressed in decimal
in a multidigit number with each corresponding digit in
another multidigit number and to display individually the ’ form.
Each of the basic comparison circuits (for example, the
results of each comparison by the lighting and extinguish
circuits
within dashed rectangle 4) contains two indicating
ing of information-representing indicating lamps.
lights, for example, neon lamps, 5 and 6. Accordingly,
Information comparison circuits are well known in the
art, illustrative of which are those shown in FIGS. 7 and
8 of the United States Patent 2,981,806, granted on April
in the A column there will be two columns of indicating
lights, one column being composed of ten lights corre
sponding to and including light 5, and the other column
25, 1961, to J. K. Middaugh. Such circuits ?nd utility
being composed of ten indicating lights corresponding to
not only in telephone switching and service-observing cir
and including light 6. The ?rst of these columns, i.e., that
cuits but in computers and other types of data-handling
which contains light 5, relates to the ?rst (or A) digit of
apparatus. Although such circuits are widely employed,
reference number; and the second of the columns, i.e.,
they do not in general provide a visual indication of data 25 the
that which contains light 6, relates to the ?rst (or A) digit
comparison results; and even where visual indication is
of the compared number.
provided, it is not individual with respect to the sever?
In addition to the previously-mentioned circuit elements
elements in multielement items of information but is in
appearing in the ?gure, it will be understood that there
stead effective only to indicate whether or not a complete
30 are included a plurality of relays corresponding to relay
correspondence has occurred.
7 which, although not speci?cally shown, are nevertheless
It is one general object of this invention to improve
intended to be included within the rectangles 8 . . . 9.
comparison display circuits.
These relays are effective, when suitably activated by th
It is another object of this invention to provide visual
sequential stepping device 3, selectively to apply vertical
indication of the results of comparison of corresponding
column activating potentials to the vertical matrix leads
35
individual elements of information in multielement items
10 and 11 . . . 12. As will be presently seen, whenever
and to present a continuing dislay of the value or" the com
pared elements when agreement occurs.
It is yet another object of this invention to display con
tinuing representations of the values of both the com
pared and comparing elements of information when such
elements do not agree in order that the values of each may
the ?rst digit of either a reference number or compared
number is introduced to the equipment, the sequential
stepping device 3 under control of either the reference
40 number source 1 or the compared number source 2 ap
plies ground to conductor 13 thereby operating relay 7
and applying ground via the front contacts thereof to the
A column vertical matrix conductor 10.
Consequently, in accordance with one feature of this
The horizontal matrix conductors are twenty in num
invention, a plurality of indicating lights are arranged in 45 ber, ten which severally represent the ten possible values
pairs of columns with each column representing an ele
of a decimal digit in each reference numeral, and ten
ment of information, with each diiferent light within a
which severally represent the ten possible values for each
column representing a different one of the possible values
compared number numeral. The uppermost (or 0) con
which the element may have, and with the two columns
ductors which emerge from number sources 11 and 2 ex
of a pair severally representing two elements which are 50 tend horizontally through each of the A0, B0 . . . NO
to be compared.
basic comparison circuits of the matrix. Similarly, the
In accordance with another feature of the invention,
1 leads extend horizontally through the Al~Nl basic cir
be preserved.
two transistors are interconnected through a third tran
cuits, the 2 leads extend horizontally through the A2-N2
sistor to form a relatively simple and rapidly-responsive
basic circuits, and the 9 leads extend horizontally through
comparison circuit which is effective not only to e?ect a 55
the
A9—N9 basic circuits.
comparison of information elements but in addition to
The circuits herein described contemplate the intro
activate selectively a pair of indicating lights.
duction of all the digits of a reference number prior to
These and other objects and features of the invention
the introduction of any one of the digits of the number
will be apparent from the following description, by way of
to be compared. However, it will be apparent from the
example, with reference to the drawing in which the single 60 following description that if it were desired to introduce
FIGURE depicts in schematic and block diagram form
one elementary embodiment of the invention.
the B—N digits only after the preceding digits have been
introduced and compared, the stepping device 3 could be
As the description proceeds, it will become apparent
modi?ed to provide sequential stepping from one of the
that the selected embodiment contemplates the presenta~
vertical columns of basic circuits to the next only after
tion of information in decimal digit form, that each item 65 both digits relating to a given numerical position have
of information is a decimal number, and that the elements
been received. In such event, each pair of corresponding
of information are the several numerals which comprise
digits will be compared as the information is introduced,
but the matrix circuits, including those similar to the
the number. However, it will be apparent also that the
circuits
dashed rectangle 4, will remain unchanged.
principles underlying the invention could be readily adapt
Now turning more speci?cally to the operation of the
ed to other forms of expression without departing from
the spirit or scope of the invention.
From a visual inspection of the ?gure, it will be seen
circuits, it may be assumed that reference number source
1 is any one of a wide variety of number sources such as,
3,090,942
3
for example, punched paper tape, decimal registers, manu
ally' operated ‘keys, etc., the particular type of which'is
unimportant to the invention. Similarly, compared num
ber source 2 may be any one of a wide variety of number
sources such as those mentioned above.
As stated before, it has been assumed that the reference
numberis presented in its entirety to the circuits prior
to the introductionof any one of the compared digits.
Accordingly, ‘as each digit is introduced by the reference
number source, the sequential stepping device transfers
ground from one of its output conductors (for example,
conductor 13) to the next conductor (for example, con
ductor 14). Initially, however, when the ?rst numeral is
4
mates that of ground. Consequently, transistor 25 re
sides in its high impedance state and the positive voltage
provided by source 34 is impressed upon serially-con
ected resistors 35 and 29 which act as a voltage divider.
Consequently, a part of the voltage ‘appears at junction
26. Asymmetrical current device 27 acts to block any
substantial attenuation that might otherwise occur as a
result of shunting through the circuits of transistor 17,
and this part of the voltage from source 34 therefore
appears at the upper terminal of light 5. This voltage
together with the negative potential conveyed to the lower
terminal of light 5 is su?icient to sustain conduction
but not to initiate it. It will thus be seen that in order '
presented by the reference number source, it ?nds the
sequential stepping device in a state in which 'groun'd’is 15 for the light 6 to be activated, it is requisite that positive
potential be applied to the upper terminal thereof; where
applied to operate ‘relay 7 via conductor 13.
as'in order for light 5 to be activated it is requisite that
Normally, when none of the vertical and horizontal
matrix conductors is conditioned to an information-repre
additional positive potential, over and above that sup
plied from source 34, be applied to its upper terminal.
senting state, each of the column relays (corresponding to
The effect of enabling the A digit column by operating
and including relay 7) is released and a modest positive 20
relay '7 will now be considered. When relay 7 is oper
potential is applied to the matrix vertical conductors ‘10
and 11 . . . 12.
‘In addition, each of the ten reference
number source horizontal conductors 0-9 and each of the
ten compared number source horizontal conductors 0—9
ated, the heretofore-mentioned moderate positive poten
tial is removed from conductor 1!) and the conductor is
grounded at the contacts of the relay. Since the emitters
are open circuited by apparatus ‘(not shown) within the 25 of transistors 17 and 18 are grounded, these transistors
are switched to their high impedance states thereby e?ec
squares 1 and 2.
en it is desired to condition a matrix
tively disconnecting the emitters from their respective
vertical conductor to an information-representing state,
collectors. No noticeable change in the potentials at the
the moderate positive potential is removed and the con
upper terminals of the indicating lamps 5 and 6 occurs,
ductor is grounded. On the other hand, when it is de
sired to condition one of the horizontal leads to an in 30 however, because the transistor collectors remain near
ground potential by virtue of the aforementioned open
' formation-representing state, a‘ relatively high positive
circuit condition of conductors 15 and 16.v
potential is applied thereto.
If instead of being actuated, relay 7 remains unoper
To aid in an understanding of the apparatus it may
now be helpful to consider the operation of the basic cir
cuit shown within rectangle 4 which, as previously men
tioned, is repeated within the remaining rectangles Al-A9,
Ell-B9
.
.
. and N0-N9.
,
When no one of the three matrix leads passing through
a given basic circuit is conditioned to an information
representing state, the three leads will reside in the elec
trical states mentioned above. Thus, for example, con
ated, and the previously-mentioned relatively high posi
tive potential is applied by the reference number source
1 to conductor 15, no appreciable change in the potential
at the upper terminal of light 5 will occur because tran
sistor 17 will be in its conducting state and most of
the relatively high positive potential will be dissipated
vas a voltage drop across resistor 36.
Similarly, if relay
7 is unoperated when relatively high positive potential
is applied to conductor 16, little or no change takes place
sidering the circuits of rectangle 4, conductor 10 will be
in the voltage ‘at the collector of transistor 18, again
energized with a modestpositive potential, and the 0 con
because the applied potential appears almost wholly as
ductors 15 and 16 ‘will be open circuited. Since the base
of transistor 18 will be positive with respect to its emitter, 45 a voltage drop across resistor 37. However, if the posi
tive potentials are applied While relay 7 is actuated, the
the transistor will exhibit a relatively low impedance
potentials at the upper terminals of lights 5 and 6 are
beween its emitter and collector. Consequently, its col
lector will reside substantially at ground potential.
The ' ’
collector of tnansistor 17 ?oats electrically, since conduc
changed su?iciently to result in activation thereof.
Normally, it might be expected that a reference digit
tor 15 is open circuited and asymmetrical current device 50 I would be introduced into the circuits before the corre
27 eifectively isolates the collector from other external
circuitry.
sponding compared digit. Consequently, positive poten
tial ‘Would be applied to conductor 15 in advance of po
t-ential application to conductor 16. 'When, while relay
The importance of the states of the transistors resides
7 is operated, the previously-mentioned relatively high
in the effects they have upon the potentials existing at
the upper'terminals of the indicating lights 5 and 6. The 55 potential is applied to conductor 15, it is conducted with
little attenuation via resistor 36, asymmetrical current
lower terminals of the indicating lights are fed indi
device 27, and resistor 28 to the upper terminal of light
vidually with negative potentials conducted from the taps
5. Since transistor 17 is in its cut-off state, it does not
19 and 20 of voltage dividers 21 and 22, the undivided
negative potential being derived from battery 23 via reset
shunt the path, and since conductor 16 is open circuited,
switch 24. The value of ‘the potential at the lower ter 60 the voltage at the base of transistor 25 is insu?‘icient to
bias transistor v25 into a low impedance condition. There
minal of indicating light 6, although sufficient to sustain
conduction by the light when activated, is insuii’icient to
'fore, transistor 25 does not shunt the previously traced
path from conductor 15 to light 5.
V
cause initial ignition. On the other hand, the potential
at the lower terminal of light 5 is insul?cient even to
The relatively high potential conducted to the upper
sustain conduction.
,
65 terminal of light 5 'is su?icient (when added to the neg
An inspection of the drawing will reveal that the col
ative potential appearing at the lower terminal of the
lector of transistor 25 is connected to the junction 26
light) to initiate conduction and a resulting glow. Once
of asymmetrical current device 27 and resistors 28 and 29.
conduction has begun, it will continue as long as tran
Accordingly, itmight be expected that the’ condition of
sistor 25 remains in its high impedance state or until
transistor 25 will in?uence the potential that may'at any 70 reset switch 24 is opened, for the potential from source
given time be present at the upper terminal of light 5.
34, when not shunted to ground by transistor 25, is suffi
Normally, :When either the previously-mentioned posi
"tive potential is applied to the base of transistor 18, or
conductor 16 is open circuited, the potential appearing
cient in aiding the previously-mentioned negative voltage
to retain light ‘5 in its conducting state.
Now if it may be assumed that sometimes subsequently
at the junction 3ti'of resistors 31,, 32, and 33 approxi 75 the corresponding compared digit is introduced, relay 7
3,090,942
5
will ‘be operated; and if it may be assumed that a match
occurs, a relatively high potential will be extended via
conductor 16 and resistor 37 to the collector of transistor
18. If transistor 18 were conducting, the potential would
be almost wholly dissipated across resistor 37. How
ever, since relay 7 is actuated, transistor 18 is in its
ing device of said ?rst pair and to the other indicating de
vice of said second pair, means including said ?rst means
responsive to the receipt of a predetermined item of in
formation from said ?rst source of information for activat
‘ing said one indicating device of said ?rst pair, and means
including said second means responsive to the receipt of
high impedance state, and the potential passes almost
undiminished to both the base of transistor 25 and to
the upper terminal of light 6. Light 6 is activated by
this potential added to the previously-mentioned negative
an information item from said second source of informa
voltage derived from Voltage divider 22.
At transistor 25, the positive voltage impressed on the
base forward-biases the emitter junction thereby lowering
the collector-to-emitter impedance to a very ‘low value.
Consequently, the voltage at junction 26 approaches
6
?rst means connecting said ?rst source of information to
one indicating device of said ?rst pair and to one indicat
ing device of said second pair, a second means connect
ing said second source of information to the other indicat
tion when said information item corresponds to said pre
determined item of information for activating said other
indicating device of said ?rst pair and for deactivating
15 said one indicating device of said ?rst pair.
ground, the remaining potential across light 5 is insuf?
cient to sustain conduction, ‘and the light is extinguished.
When the potential on conductor 16 reverts to zero,
2. Apparatus comprising a ?rst pair of indicating de
vices each representing an identical item of information,
a second pair of indicating devices both representing a
different item of information, each of said ?rst and said
transistor 25 is changed back to its high impedance state.
second pair of indicating devices being initailly inactive, a
However, no change in the conditions of the lights takes 20 ?rst source of information, a second source of informa
place, light 5 remaining extinguished and light 6 remain
ing lit. Light 6, together ‘with any other activated light
tion, a ?rst means connecting said?rst souroe of informa
tion to ‘one indicating device of said ?rst pair and to one
in the array may be extinguished by opening the reset
indicating device of said second pair, a second means con
switch 24.
necting said second source of information to the other in
25
If, instead of there having been a match, there had
dicating device of said ?rst pair and to the other indicating
been a dissimilarity, the light 5 would have remained
device of said second pair, means including said ?rst
lit and a light corresponding to light 6 but located in one
means responsive to the receipt of a predetermined item
of the rectangles A1-A9 would have been activated.
of information from said ?rst source of information for
Thus, for example, if the compared digit had been a 1
activating said one indicating device of said ?rst pair, con
instead of 0, conductor 16 would have been left open
trol means including said second means responsive to the
circuited, the potential at the upper terminal of light 6
receipt of an information item from said second source of
would not have been raised to cause light 6 to initiate
information when said information item corresponds to
conduction, and transistor 25 would have remained in its‘
said predetermined item of information for activating
high impedance state thereby leaving unaffected the po 35 said other indicating device of said ?rst pair, said last
tentials requisite to the continued conduction of current
mentioned means being responsive to the receipt of said
by light 5. In rectangle 38, the light corresponding to
information item when said information item and said
light 6, i.e., light 39, would have been lit to indicate the
predetermined item disagree for retaining said other in
number 1. Consequently, when corresponding digits do
dicating device of said ?rst pair in an inactivated state, and
not match, both of the lights which severally represent 40 means activated by said control means for deactivating
the reference and compared digits remain lit to preserve
said one indicating device of ‘said ?rst pair when said
visual indications of the values thereof.
other indicating device of said ?rst pair is activated.
It should now be apparent that under control of the se
3. Apparatus comprising a ?rst pair of electrical ele
quential stepping device 3, the column-activating relays
ments each representing an identical item of information,
a second pair of electrical elements both representing a
a time, and that the reference and compared number 45 different item of information, each of said ?rst and said
sources 1 and 2 operate in cooperative association with the
second pair of electrical elements being initially inactive,
7 and 8 . . . 9 sequentially enable the columns one at
column-activating relays to provide activating potentials
a ?rst source of information, a second source of informa
which are selectively impressed upon the horizontal matrix
tion, a ?rst means connecting said ?rst source of informa
tion to one element of said first pair and to one element
of said second pair, a second means connecting said sec
ond source of information to the other element of said
conductors to represent values of the digits which are to
be compared. Thus, selected ones of the basic compari
son circuits are activated to display continuing visual in
dications of the values of the digits and the results of
?rst pair and to the other element of said second pair,
means including said ?rst means responsive to the receipt
While I have illustrated my invention by a particular
of a ?rst predetermined item of information for activat
embodiment thereof, the invention is not limited in its 55 ing :said one element of said ?rst pair and responsive to
application to the speci?c apparatus and particular ar
the receipt of a second predetermined item of informa
rangement herein disclosed. Various applications, modi
tion for activating said one element of said second pair,
?cations, and arrangements of the invention will readily
and means including said second means responsive to the
comparison.
occur to those skilled in the art.
receipt of an item of information when said an item
The terms and expressions which I have employed in 60 corresponds to said ?rst predetermined item for activating
reference to the invention are used as terms of descrip
said other element of said ?rst pair and for deactivating
tion and not of limitation, and I have no intention in the
said one element of said ?rst pair, said last-mentioned
use of such terms and expressions of excluding equivalents
means being responsive to the receipt of an item of infor
of the features shown and described or parts thereof, but _
mation when said an item corresponds to said second pre
on the contrary, intend to include therein any and all 65 determined item of information for leaving activated said
equivalents, modi?cations, and adaptations which may
be employed without departing from the spirit of the
one element of said ?rst pair and for activating said other
element of said second pair.
4. Apparatus comprising a ?rst plurality of indicating
invention.
What is claimed is:
devices each representing a different one of a ?rst plurality
70
1. Apparatus comprising a ?rst pair of indicating de
of values expressible by a ?rst digit, a corresponding plu
vices each representing an identical item of information,
rality of indicating devices each representing a different
a second pair of indicating devices both representing a dif
one of a plurality of values expressible by a second digit
‘ferent item of information, each of said ?rst and said sec
and severally corresponding to the values of said ?rst plu
ond pair of indicating devices being initially inactive, a ?rst
75 rality of values, each of said first and said corresponding
source of information, a second source of information, a
‘3,090,942
plurality of indicating devices being initially inactive, a
?rst plurality of conductors in combinations selectively
representing the values expressible by said ?rst digit, a
second plurality of conductors including certain of said
?rst plurality of conductors in other combinations selec
tively representing the values expressible by said second
digit, means for selectively activating said conductors in
8
second means interconnecting said second transistor with
said second indicating lamp, means including said ?rst
interconnecting means and said ?rst transistor responsive
to the receipt of a ?rst selected signal at said ?rst tran
sistor for lighting said ?rst indicating lamp, a third tran
sistor interconnecting said ?rst transistor with said second
transistor, means including said second interconnecting
any of said combinations, means responsive to the activa
means and said second transistor responsive to the receipt
tion of any combination of said ?rst plurality of conduc
of a second selected signal at said second transistor for
tors for activating the corresponding one of said ?rst plu 10 lighting said second indicating lamp, and means including
rality of indicating devices, means responsive to the acti
vation of any combination of said second plurality of
conductors for activating the corresponding one of said
said third transistor for extinguishing said ?rst indicating
lamp when both said ?rst and said second indicating lamps
‘are lighted.
corresponding plurality of indicating devices, and means
8. Apparatus comprising a ?rst source of information,
activated by said last-mentioned means for deactivat 15 a second source of information, a ?rst plurality of ele
ing the activated corresponding one of said ?rst plurality
ments capable of being each separately triggered from a
of indicating devices when said one of said corresponding
?rst stable electrical state to a second stable state and
plurality of indicating devices is activated.
each representing a different item of information, a second
5. Apparatus comprising a ?rst plurality of indicating
plurality of elements capable of being each separately
devices each representing a different one of a ?rst plurality 20 triggered from a ?rst stable electrical state to a second
of Values expressible by a ?rst digit, a corresponding plu
rality of indicating devices each representing a di?ferent
one of a plurality of values expressible by a second digit
stable state and each representing a different item of in
formation, each of said ?rst and said second plurality of
elements being initially in the same stable electrical state,
and severally corresponding to the values of said ?rst plu
means connecting said ?rst source of information to said
rality of values, each of said ?rst and said corresponding 25 ?rst plurality of elements for triggering that element rep
plurality of indicating devices being initially inactive, a
resenting the item of information supplied by said source
?rst plurality of conductors in combinations selectively
from said ?rst to said second state, means connecting said
representing the values expressible by said ?rst digit, a sec
second source of information to said second plurality of
ond plurality of conductors including certain of said ?rst
elements for triggering that element representing the item
plurality of conductors in other combinations selectively 30 of information supplied by said source from said ?rst to,
representing the values expressible by said second digit,
said second state, and means interconnecting said ?rst
means for selectively activating said conductors in any of
plurality of elements and said second plurality of elements
said combinations, means responsive to the activation of
for triggering that element of said ?rst plurality in said
any combination of said ?rst plurality of conductors for
second state back to said ?rst state if said items of infor
activating the corresponding one of said indicating de 35 mation from said ?rst and second sources correspond.
vices, means responsive to the activation of any combina
9. Information ‘comparison circuits comprising a ?rst
tion of said second plurality of conductors for activating
source of information, a second source of information, a
‘the corresponding one of said corresponding plurality of
?rst element capable of assuming two different electrical
indicating devices, and means e?ective'when said any
states, a second element capable of assuming two different
I combination of said second plurality of conductors rep 4-0 electrical states, said ?rst and said second element being
resents the value expressed by said any combination of
both initially in the same one of said two different states,
said ?rst plurality of conductors for deactivating the corre
a ?rst means interconnecting said ?rst source of informa
sponding indicating device of said ?rst plurality.
tion and said ?rst element, said ?rst means being respon
'6. Digit comparison circuits comprising a ?rst plurality
sive to the receipt of a predetermined item of informa
of indicating devices arranged in subplur‘alities in ?les 45 tion from said ?rst source for triggering said ?rst element
each referable to a different digit position in a multidigit
from a ?rst to a second electrical state, asecond means in
number, each of the indicating devices in a subplurality
terconnecting said second source of information and said
being representative of a different one of the possible
second element, said second means being responsive to
values of the digit which may occupy the position to ‘which
the receipt of a predetermined item of information from 7
said subplurality is referable, a ?rst source of multidigit 50 said second source for triggering said second element from
numbers, means connecting said ?rst source to said ?rst
plurality of indicating devices responsive to the receipt of
a multidigit number from said ?rst source for selectively
activating the indicating devices representing the values
of the digits in said number from said ?rst source, a sec
ond plurality of indicating devices arranged in other sub
pluralities in ?les each referable to a different digit posi
tion in another multidig-it number, each of the indicating
devices in each of said other subpluralities being repre
a ?rst to a second electrical state, and means intercon
necting said ?rst element and said second element for
causing said ?rst element to change its electrical state
from said second state back to said ?rst state if said pre
55 determined items of information vfrom said ?rst and sec
ond sources correspond.
10. Apparatus comprising a ?rst pair of indicating de
vices each representing an identical item of information,
a second pair of indicating devices both representing a
sentative of a different one of the possible ‘values of the 60 different item of information, each of said ?rst and said
digit which may occupy the position to which said each
‘second pair of indicating devices being initially inactive,
of said other subpluralities is referable, a second source
a ?rst source of information, a second source of informa
vof multidigit numbers, means connecting said second
tion, a ?rst means connecting said ?rst source of in
source to said second plurality of indicating devices re
formation to one indicating device of said ?rst pair and to
sponsive to the receipt of a multidigit number from said 65 one indicating device of said second pair, a second means
second source for selectively activating the indicating de
connecting said second’ source of information to the
vices representing the values of the digits in said multi
other indicating device of said ?rst pair and to the other
digit number from said second source, and means for
indicating vdevice of said second pair, means including
individually comparing the digits in each said di?erent
said ?rst means responsive to the receipt of a predeter
digit position and when the digits in any digit position 70 mined item of information from said ?rst source of in?
correspond for deactivating in said any digit position the
formation for activating said one indicating device of said
, indicating device of said ?rst plurality of indicating devices.
?rst pair, and means including said second meansrespon
7. Apparatus comprising a ?rst and a second transistor,
sive-to the receipt of an information item from said second
a ?rst and a second indicating lamp, ?rst means intercon
source of information when said information item cor
necting said ?rst transistor with said ?rst indicating lamp, 75 responds to said predetermined item of information for
3,090,942
activating said other indicating device of said ?rst pair
and for deactivating said one indicating device of said ?rst
pair, said last-mentioned means being responsive to the
receipt of said information item When said information
item and said predetermined item disagree for retaining
said one indicating device of ‘said ?rst pair in an activated
state and for activating said other indicating device of
said second pair ‘if said information item is that item of
10
a ?rst selected signal at said ?rst transistor for lighting
said ?rst lamp, fourth means including said second means
and said second transistor operable in response to the
receipt of a second selected signal at said second transistor
for lighting said second lamp, and ?fth means intercon
necting said ?rst and said second transistor for render
ing said fourth means inoperative to prevent the lighting
of said second lamp when said ?rst lamp is lit.
information that said second pair of indicating devices
13. Apparatus comprising a pair of indicating devices
source of information, a second source of information,
?rst means including a ?rst element coupled to said ?rst
information, ?rst means connecting said ?rst information
10 each representing an identical item of information, each
is intended to represent.
of said indicating devices of said pair being initially in
11. Information comparison circuits comprising a ?rst
active, a ?rst source of information, a second source of
source to one of said pair of devices, second means con
one electrical state, second means including a second ele 15 necting said second information source to the other device
of said pair, third means including said ?rst means respon
ment coupled to said second information source and
information source and capable of assuming more than
sive to the receipt of a predetermined item of information
capable of assuming more than one electrical state, each
from said ?rst information source for activating said
of said ?rst and second elements being initially in the
one device of said pair, fourth means including said second
same electrical state, said ?rst means responsive to the
receipt of a predetermined item of information from 20 means operable in response to a predetermined item of
information from said second source for activating said
said ?rst source for causing said ?rst element to assume
other device of said pair, and means controlled by said
an electrical state corresponding to said information item
third means for rendering said fourth means inoperative
from said ?rst source, said second means responsive to
to prevent the activation of said other device of said pair
the receipt of an item of information from said second
information source for causing said second element to 25 only when said predetermined item of information from
said second information source is identical with said pre
assume an electrical state corresponding to said item of
determined item of information from said ?rst informa
information from said second source, and means inter
tion source.
connecting said ?rst means and said second means for
rendering said ?rst element electrically ineffective to as
sume said electrical state corresponding to said item of
information from said ?rst source if said predetermined
item and said item of information from said second
source of information correspond.
12. Apparatus comprising a ?rst and a second tran
sistor, a ?rst and a second indicating lamp, ?rst means 35
interconnecting said ?rst transistor with said ?rst lamp,
second means interconnecting said second transistor with
said second lamp, said ?rst and said second lamp being
initially extinguished, third means including said ?rst
References Cited in the ?le of this patent
UNITED STATES PATENTS
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Kreiner ______________ __ Sept. 30,
Knutson ______________ __ July 12,
Hobbs ______________ __ Mar. 19,
White et a1 ____________ __ Nov. 8,
1952
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OTHER REFERENCES
Publication: High Speed Computing Devices, by En
gineering Research Associates, published by McGraw-Hill
means and said ?rst transistor responsive to the receipt of 40 Book Co., Inc., New York, 1950, pp. 15-19 relied on.